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Reading slicks

Posted By: Jacob Pitt

Reading slicks - 03/23/11 05:57 PM

Hey guys just switched the radials off my Challenger and went back to the biasply slicks. I put ten passes on them Saturday during the bracket race but never really got them broke in. They are still smooth on 90% of the tire like it has never touched the track. They weren't hooking very good either as my 60' was off about .08 all day until the semi's where it picked up .04 in the 60'. My real question is, how can you tell if you have to much air pressure or not enough? I started off with 12psi, then 11, then 10 with no real changes in performance. The center of the tire still has the mold strip down it like it has never touched.
Posted By: Cab_Burge

Re: Reading slicks - 03/23/11 06:14 PM

Which brand and size tires and what size width rim? We use to run 15 to 17 lbs on a nine inch bias ply tire on a ten inch rim years ago before the radials came out for use in NHRA stock class I'm pretty sure there was a change in the tire construction or compuond before those tires(Firestones) where being bought, we use to use (before that) 9 to 12 lbs on the same size tires and rims The M/T liked less air than the Firestones tires did in the same size on the same rims and car
Posted By: Guitar Jones

Re: Reading slicks - 03/23/11 06:18 PM

If the outer edges of the tire are only being used than you don't have enough pressure. Conversely if the center is the only part being used than you have too much air pressure.
Posted By: ram87

Re: Reading slicks - 03/23/11 06:26 PM

Jacob - Find a clean place to launch your car so you can read the rubber patch that is laid down. Light in the middle is not enough air. Light on the edges is too much air. Even color the full width of the tire is just right. I used to use my driveway but then I have a long wide driveway and my neighbors don't mind the noise. I would think reading the tire wear in the center is to much air. Wear on the edges is to little air and wear all the way across is just right.
Posted By: Cab_Burge

Re: Reading slicks - 03/23/11 06:37 PM

Quote:

If the outer edges of the tire are only being used than you don't have enough pressure. Conversely if the center is the only part being used than you have too much air pressure.


that is what we used on the firestones, that didn't work on the M/T Tire ressure and 60 ft. times is what your going to have tomake the decision with. I use to slide my fingertips across the tire with very light pressure, if the edges(on NEW tires) where smooth and the rest of the tire was rough then I let some air out a little at a time until the roughness was the same and the time slip showed a good 60 ft. If the edges where rough and then went smooth and then rough in the center and smooth before the edges on the other side of the tire and the far edge was rough I would pump them up 2 oor 3 lbs or more as needed until I got a constitent texture all the way across and better 60 Ft times Ultimately your going to have to figure what theses tires want on your car
Posted By: MR_P_BODY

Re: Reading slicks - 03/23/11 06:54 PM

Quote:

Hey guys just switched the radials off my Challenger and went back to the biasply slicks. I put ten passes on them Saturday during the bracket race but never really got them broke in. They are still smooth on 90% of the tire like it has never touched the track. They weren't hooking very good either as my 60' was off about .08 all day until the semi's where it picked up .04 in the 60'. My real question is, how can you tell if you have to much air pressure or not enough? I started off with 12psi, then 11, then 10 with no real changes in performance. The center of the tire still has the mold strip down it like it has never touched.




Being that they were new you need to do a GOOD burn
out the first time(most brands) that breaks the surface
and gets the resins up... also like the others said
no marks in the center you need more air and the
other way as said
Posted By: Jacob Pitt

Re: Reading slicks - 03/23/11 08:04 PM

Quote:

Quote:

Hey guys just switched the radials off my Challenger and went back to the biasply slicks. I put ten passes on them Saturday during the bracket race but never really got them broke in. They are still smooth on 90% of the tire like it has never touched the track. They weren't hooking very good either as my 60' was off about .08 all day until the semi's where it picked up .04 in the 60'. My real question is, how can you tell if you have to much air pressure or not enough? I started off with 12psi, then 11, then 10 with no real changes in performance. The center of the tire still has the mold strip down it like it has never touched.




Being that they were new you need to do a GOOD burn
out the first time(most brands) that breaks the surface
and gets the resins up... also like the others said
no marks in the center you need more air and the
other way as said





They are M/T 31*13 on a 10" rim. It has been a couple of years since I ran these tires because I switched to the 31.25*12.2 M/T Radial. It seems like these tires may have changed some. I was doing pretty aggresive burnouts all night to try and get them to come in, but they never did. I'm taking the car out tonight and I'll try air pressure the other direction. Just seems like a lot of pressure to run.
Posted By: MR_P_BODY

Re: Reading slicks - 03/23/11 08:08 PM

They are M/T 31*13 on a 10" rim. It has been a couple of years since I ran these tires because I switched to the 31.25*12.2 M/T Radial. It seems like these tires may have changed some. I was doing pretty aggresive burnouts all night to try and get them to come in, but they never did. I'm taking the car out tonight and I'll try air pressure the other direction. Just seems like a lot of pressure to run.




If they're old they could be dried out(no resin left)
Posted By: Jacob Pitt

Re: Reading slicks - 03/23/11 09:20 PM

They are brand new. 10 passes total.
Posted By: DusterKid

Re: Reading slicks - 03/23/11 10:58 PM

I run 11 lbs in a 29.5x13.5 slick on a 12" rim and they wear pretty good. before that I ran a 29.5x11.5 and ran I think 10 1/2 lbs if I remember correctly.
Posted By: 408strokerdart

Re: Reading slicks - 03/23/11 11:52 PM

Tubes or no tubes? I run that same tire on a 12" wheel and run just under 13 lbs cold. From some of my launch pictures it looks like it could stand a little more air even. That much air pressure is strange for me since I grew up on Goodyears running 6-7 lbs.
Posted By: Cab_Burge

Re: Reading slicks - 03/24/11 02:52 AM

Quote:

They are brand new. 10 passes total.


What brand and who did you buy them from Thumperdart bought a set of drag tires several years ago from Summit, one came from the Sparks, NV wharehouse and the other one came form Ohio, one of them was 18 months old and the other one was around 13 months old There is a code on the side of the tire that shows when it was made Let us know how old they are A long time ago I bought two sets of Firestones stocker tires at the beginning of the year, I had both sets mounted and balanced and put the spare set in the back shop off the ground and covered up I ran the fisrt set for four races and part of the 5th divisional races, no bracket racing on them. I put the second set on at the fifth divisional race after making seeveral passes on the old set on the test and tune day. The new set wouldn't hook hardily at all Luckily for me the west coast dealer for Fiirestone racing tires was there and ended up replacing them for free Not all new tires are always good
Posted By: Anonymous

Re: Reading slicks - 03/24/11 03:01 AM

12.5-13 lbs. when new.
1st pass. do a real good burnout.
Posted By: Jacob Pitt

Re: Reading slicks - 03/24/11 03:24 AM

Went out tonight for T&T night. Went up to 13lbs and the center finally showed some wear. Also tightened up the extension after it spun pretty good on the second pass and the 60' went from a 1.41 to a 1.33 which is where it should be. They are a little slower than the radials but still went a 6.07.
Posted By: Cab_Burge

Re: Reading slicks - 03/24/11 06:24 PM

Quote:

Went out tonight for T&T night. Went up to 13lbs and the center finally showed some wear. Also tightened up the extension after it spun pretty good on the second pass and the 60' went from a 1.41 to a 1.33 which is where it should be. They are a little slower than the radials but still went a 6.07.


Good find It is not uncommon for the radials to be faster on a good track
Posted By: Aspen7695

Re: Reading slicks - 03/24/11 06:39 PM

My car is .15 faster on the radials.

Raul
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